Protanilla Taylor, 1990

Taxonomy. The genus Protanilla is assigned to the tribe Anomalomyrmini (Bolton 1990c, 2003). The tribe Anomalomyrmini was recently revised, and Protanilla was redefined by Borowiec et al (2011).

Morphology. Workers of Vietnamese species have the following features (see also Bolton 1990c and Borowiec et al. 2011):

Worker monomorphic; head in full-face view somewhat elongate trapezoidal; preoccipital carina present but weak dorsally and laterally on head; frontal lobe, frontal carina and antennal scrobe absent; antennal sockets in fullface view fully exposed, very close to anterior margin of head, widely separated from each other by clypeal disc; clypeal disc trapezoidal, raised, and flattened or weakly concave medially, margined laterally with a sharp edge running from mandibular insertion to junction with frons; mandibles subtriangular; masticatory margin of mandible with small peg-like teeth; inner surface of mandible with peg-like teeth (modified setae) and thick setae; antenna 12-segmented; eye absent (but intercaste often with reduced eye consisting of a few ommatidia); mesosoma in lateral view with almost straight dorsal outline, or promesonotum feebly raised; promesonotal suture present and flexible; metanotal groove conspicuous dorsally; propodeum unarmed; orifice of propodeal spiracle round, situated relatively low on lateral face of propodeum; propodeal lobe absent; waist consisting of two small segments (petiole and postpetiole) which have clearly differentiated posterior faces; petiole without anterior peduncle; its tergosternal fusion complete, without trace of sutrue; its sternite swollen strongly and forming anteroventral flange; petiolar and postpetiolar spiracles located on the side of anteriormost part of the petiolar and postpetiolar nodes, respectively; postpetiole almost as long as or longer than broad, not distinctly broader than petiole, lacking tergosternal fusion; its sternite swollen strongly; abdominal spiracles V–VII concealed by the posterior margins of the preceding segments; pygidium large, convex across its width, laterally and posteriorly unarmed; sting well developed.

Differentiation. The worker of Protanilla is easily distinguished from that of the other genera known from Vietnam by a combination of features: antennal sockets in full-face view fully exposed; clypeal disc trapezoidal, raised and flattened, margined laterally with a sharp edge; inner surface of mandible with peg-like teeth; promesonotal suture present and flexible; waist consisting of two small segments (petiole and postpetiole) which have clearly diffintiated posterior faces.

Vietnamese species (3 spp.).

P. sp. eg-1 (Tay Yen Tu). P. sp. eg-3 (Cat Tien).

P. sp. eg-4 (Bidoup-Nui Ba).

Bionomics. Protanilla spp. usually occur in well-developed forests but sometimes in forest edges. They nest in rotten wood fragments and in soil.